set(CMAKE_SYSTEM_NAME Generic)
set(CMAKE_SYSTEM_PROCESSOR AVR)

if(MINGW OR CYGWIN OR WIN32)
    set(UTIL_SEARCH_CMD where)
elseif(UNIX OR APPLE)
    set(UTIL_SEARCH_CMD which)
endif()

set(TOOLCHAIN_PREFIX avr-)

execute_process(
  COMMAND ${UTIL_SEARCH_CMD} ${TOOLCHAIN_PREFIX}gcc
  OUTPUT_VARIABLE BINUTILS_PATH
  OUTPUT_STRIP_TRAILING_WHITESPACE
)

get_filename_component(ARM_TOOLCHAIN_DIR ${BINUTILS_PATH} DIRECTORY)
set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)

set(CMAKE_C_COMPILER ${TOOLCHAIN_PREFIX}gcc)
set(CMAKE_ASM_COMPILER ${CMAKE_C_COMPILER})
set(CMAKE_CXX_COMPILER ${TOOLCHAIN_PREFIX}g++)

set(CMAKE_OBJCOPY ${ARM_TOOLCHAIN_DIR}/${TOOLCHAIN_PREFIX}objcopy CACHE INTERNAL "objcopy tool")
set(CMAKE_SIZE_UTIL ${ARM_TOOLCHAIN_DIR}/${TOOLCHAIN_PREFIX}size CACHE INTERNAL "size tool")

set(CMAKE_FIND_ROOT_PATH ${BINUTILS_PATH})
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

set(MCU "atmega328p")
add_compile_options("-mmcu=${MCU}" "-DF_CPU=16000000UL")
add_link_options(
    -mmcu=${MCU}
    -funsigned-char # a few optimizations
    -funsigned-bitfields
    -fpack-struct
    -fshort-enums
    -ffunction-sections
    -fdata-sections
    -fno-split-wide-types
    -fno-tree-scev-cprop
    -fno-exceptions
)
